| Type: | Package |
| Title: | Repeated Evaluation |
| Version: | 0.1.1 |
| Date: | 2024-01-22 |
| Description: | Provide simple mechanism to repeatedly evaluate an expression until either it succeeds or timeout exceeded. It is useful in situations that random failures could happen. |
| License: | MIT + file LICENSE |
| URL: | https://github.com/randy3k/retry |
| Encoding: | UTF-8 |
| RoxygenNote: | 7.3.0 |
| Suggests: | testthat (≥ 2.1.0), covr |
| Imports: | rlang, later |
| NeedsCompilation: | no |
| Packaged: | 2024-01-22 23:58:37 UTC; randylai |
| Author: | Randy Lai [aut, cre] |
| Maintainer: | Randy Lai <randy.cs.lai@gmail.com> |
| Repository: | CRAN |
| Date/Publication: | 2024-01-23 00:30:03 UTC |
retry: Repeated Evaluation
Description
Provide simple mechanism to repeatedly evaluate an expression until either it succeeds or timeout exceeded. It is useful in situations that random failures could happen.
Author(s)
Maintainer: Randy Lai randy.cs.lai@gmail.com
See Also
Useful links:
Repeatedly evaluate an expression
Description
Repeatedly evaluate an expression until a condition is met or timeout is exceeded.
Usage
retry(
expr,
upon = "error",
when = NULL,
until = NULL,
envir = parent.frame(),
silent = FALSE,
timeout = Inf,
max_tries = Inf,
interval = 0.1,
later_run_now = FALSE
)
Arguments
expr |
an expression to be evaluated, supports quasiquotation. |
upon |
a vector of condition classes. The expression will be evaluated again after
the delay if a condition is thrown. See the |
when |
regular expression pattern that matches the message of the condition. It is used to
decide if we need to evaluate |
until |
a function of two arguments. This function is used to check if we need to
evaluate |
envir |
the environment in which the expression is to be evaluated. |
silent |
suppress messages and warnings |
timeout |
raise an error if this amount of time in seconds has passed. |
max_tries |
maximum number of attempts |
interval |
delay between retries. |
later_run_now |
execute |
Examples
retry(10, until = ~TRUE) # returns immediately
f <- function(x) {
if (runif(1) < 0.9) {
stop("random error")
}
x + 1
}
# keep retring when there is a random error
retry(f(1), when = "random error")
# keep retring until a condition is met
retry(f(1), until = function(val, cnd) val == 2)
# or using one sided formula
retry(f(1), until = ~ . == 2)
try({
# it doesn't capture the error of "a" + 1
retry(f("a"), when = "random error")
})
try({
# an error is raised after 1 second
retry(stop("foo"), when = "foo", timeout = 1)
})
try({
# timeout also works for indefinite R code
retry(while(TRUE) {}, until = ~FALSE, timeout = 1)
})
Wait until a condition is met
Description
Block the current runtime until the expression returns TRUE.
Usage
wait_until(
expr,
envir = parent.frame(),
timeout = Inf,
interval = 0.1,
later_run_now = TRUE
)
Arguments
expr |
an expression to check, supports quasiquotation. |
envir |
the environment in which the expression is to be evaluated. |
timeout |
raise an error if this amount of time in second has passed. |
interval |
delay between retries. |
later_run_now |
execute |
Examples
s <- Sys.time()
system.time(wait_until(Sys.time() - s > 1))
z <- 0
later::later(function() z <<- 1, 1)
wait_until(z == 1)
z == 1